Coffey Stills are a two-column continuous whiskey still named after the inventor, Aeneas Coffey. Patented in 1830, this design eliminated the need for multi-distillation and produced a spirit with a higher proof and lighter character.
The first column (called the analyzer) in a column still has steam rising and wash descending through several levels. The second column (called the rectifier) carries the alcohol from the wash, where it circulates until it can condense at the required strength.
Column stills behave like a series of single pot stills, formed in a long vertical tube. The tube is filled with either porous packing or bubble plates. The rising vapor, which is low in alcohol, starts to condense in the cooler, higher level of the column. The temperature of each successively higher stage is slightly lower than the previous stage, so the vapor in equilibrium with the liquid at each stage is progressively more enriched with alcohol.
Coffey Stills can sustain a constant process of distillation. This, along with the ability to produce a higher concentration of alcohol in the final distillate, is its main advantage over a pot still, which can only work in batches.
Nikka Whisky imported two Coffey Stills from Scotland in 1963 which are used to produce the popular Nikka Coffey Grain Whisky and Nikka Coffey Malt Whisky. Coffey stills are known for yielding greater depth and flavour then modern stills, with their unique character the signature of these Nikka products.